added assert to protect against wrap-around

1 files changed, 1 insertions, 0 deletions

diff --git a/vespalib/src/vespa/vespalib/data/simple_buffer.cpp b/vespalib/src/vespa/vespalib/data/simple_buffer.cpp
index 4fe71df1435..a9bf80ac845 100644
--- a/vespalib/src/vespa/vespalib/data/simple_buffer.cpp
+++ b/vespalib/src/vespa/vespalib/data/simple_buffer.cpp
@@ -29,6 +29,7 @@ SimpleBuffer::evict(size_t bytes)
 WritableMemory
 SimpleBuffer::reserve(size_t bytes)
 {
+    assert((_used + bytes) >= _used);
     _data.resize(_used + bytes, char(0x55));
     return WritableMemory(&_data[_used], bytes);
 }